Department of Primary Industries:  http://www.dpi.vic.gov.au  with this site follow the prompts to ‘Agriculture & Food’ where you will find some very useful sites such as the ‘Agriculture and Landcare Notes’ and ‘Small Farm Information’ (where a huge bibliography is listed under ‘publications & research’).

Department of Sustainability & Environment:  http://www.dse.vic.gov.au

Greening Australia:  http://www.greeningaustralia.org.au

The National Dryland Salinity Program:  http://www.ndsp.gov.au

Rural Industries Research & Development Corporation: http://www.rirdc.gov.au

CSIRO Land & Water: http://www.clw.csiro.au

Horse SA is a not for profit industry representative body for all horse owners, riders and enthusiasts and ATHRA is the Australian Trail Horse Riders Association; see www.athra.com.au/HorseSA.aspx

Other useful sites will be that of your local government.  For instance:

The City of Whittlesea:  http://www.whittlesea.vic.gov.au

The Nillumbik Shire Council:  http://www.nillumbik.vic.gov.au